“Your currency is runs, isn’t it?” declared Marcus Trescothick, England’s interim head coach, after the three-day victory against Pakistan at Headingley.

Trescothick was referring to Jordan Cox, who contributed an assured 73 during the innings win in Leeds.

Yet he could easily have been talking about Emilio Gay, whose fledgling England career is reaching an inflexion point heading into this week’s second Test at Lord’s.

Having made a confident start to his Test career at the beginning of the summer with half-centuries in his first two matches against New Zealand, including the first on a challenging Lord’s pitch, Gay has since struggled with 54 runs in his past four innings.

The sample size of four Tests is small. His average of 24.57 cannot be seen as a true reflection of his talent.

Yet like many who have come before him, the 26-year-old is quickly realising that the step up from the county game to the goldfish bowl that is Test cricket comes with significant added pressure and scrutiny.

The biggest barrier to progression for those lucky enough to make the leap is the constant technical analysis that accompanies representing England. Former players are quick to point out flaws and opposition bowlers are good enough to prey on them.

Gay’s knock of 33 from 31 balls in Leeds summed up a player who looks the part but who is being undermined by one glaring weakness.

The stylish left-hander’s flair is not in question – but his ability to play confidently outside off stump is, thanks to a trigger movement that sees his front foot step across to off stump and leaves him vulnerable to edging good-length balls outside off.

This is exactly what happened at Headingley when Gay was caught in the slip cordon off a Mohammad Ali delivery that angled across him and squared him up.

His trigger movement also leaves him vulnerable to being pinned lbw to balls coming onto the stumps and edging fuller balls outside off because his head falls over and he is accessing the ball outside of his eyeline.

Former England captain Nasser Hussain, speaking on Sky Sports, explained: “If we go back to the Lord’s Test (against New Zealand, below), Gay plants his front foot too far on the off side, which means he has to drag it out of the way as well as his body. Then he finds both feet are pointing down the pitch, leaving him vulnerable.

Hussain added: “You go to the dismissal today. He has to drag the whole right side of his body out of the way. We used to say to turn the body shape of a batter into an ‘S’. Once you get into that position, you can only play the adjustor, and you end up nicking it.”

This is nothing new. Just ask Tom Westley, Alex Lees, Mark Stoneman or Adam Lyth – all top-order players who had their techniques dissected during brief England careers over the past decade or so. All averaged under 30. None played more than 11 Tests.

It’s telling that six of Gay’s seven dismissals so far in Test cricket have seen him caught behind the wicket. The trigger movement is causing him issues when bowlers get it right.

That is not to say he won’t make it; just that he needs runs in the final two Tests against Pakistan to assure himself of a place on England’s winter tour of South Africa.

As Trescothick says, runs will be what Gay is judged on but fixing this technical flaw – almost impossible in the middle of a series – will make life easier.

Others are more forgiving. Two former England captains in Michael Vaughan and Sir Alastair Cook were among those who spoke in glowing terms of Gay at Headingley and insisted he just got a “good ball”.

Former England fast bowler Steve Harmison, speaking on TalkSport, went even further. “I think it’s unjust against Emilio at the minute,” he said. “Judge somebody on seven to 10 Test matches. Give them the whole summer and half the winter. That is what we should be looking at with Emilio Gay.”

Yet there are two big issues for Gay: time and competition for places. England have just eight Tests until the start of next summer’s Ashes. If they are going to make a change, it probably needs to be at the end of this series.

New Test head coach Stephen Fleming will take charge of the three-Test series in South Africa that starts in December. Deciding on his opening partnership will arguably be his biggest decision.

He has options, too, with Cox now able to state his case for continued inclusion in the XI after a positive start to life at No 3 at Headingley.

The Essex batter is only there because of an injury to Jacob Bethell. But once Bethell is back, will England keep Cox at No 3 and move Bethell up to opener? If Cox scores runs against Pakistan – and Gay doesn’t – this is a very likely scenario.

Of course, Gay can make the job of Fleming and the other selectors difficult if he finds form at Lord’s this week and in the final Test at Edgbaston. Otherwise, he could follow the fate of Westley, Lees, Stoneman and Lyth, who were all discarded after having their techniques picked apart on the most unforgiving stage of all.